基于近场技术的微纳尺度热物性测量系统空间分辨率增强

传统的脉冲激光时域热反射系统通常基于远场光学设计,对于微纳米材料热物性测量的空间分辨率约在3μm～10μm范围,不足以满足先进微电子器件和芯片的热物性测试要求.基于近场光学原理,本文研究了提升时域热反射系统空间分辨率的新颖技术方法,并建立了相应的实验系统.实验获得的微纳结构样品测量数据表明,基于近场技术的时域热反射系统...     

CT系统空间分辨率测量技术的改进

调制传递函数反映了CT系统的空间分辨率,可通过点扩展函数（PSF）,边缘响应函数（ERF）进行计算。对PSF和ERF方法分别进行改进。在PSF方法中,通过图像处理分割出点扩展区域,点扩展区域呈圆形,从而可以利用数学变换的方法找出中心点位置,并计算出MTF曲线。在ERF方法中,通过图像处理分割出体模图片中的目标线,然后对目标线进行直线拟合,再利用数学变换计算出拟合直线与垂直位置的偏移角度,从而进行相应角度的旋转。可以使ERF数据相互对应,从而直接进行平均处理。实验结果表明提出的改进方法是准确和有效的,简化了临床扫描条件,为CT系统的评估带来方便。     

一种雷达吸波涂层厚度无损检测的方法

本文介绍了一种雷达吸波涂层厚度无损检测的方法,并重点讨论了其测试结果,结果表明,该测试方法的测试结果与标准参考样板数据具有很好的吻合,该方法方便灵活,测量范围广,精度高,可用于吸波材料现场厚度质量控制。     

一种雷达吸波涂层的在线测量方法

本文介绍了一种雷达吸波涂层的在线测量方法,并重点讨论了其测试结果.该在线测量方法的测试结果具有良好的统计稳定性,测试结果和实验室测量方法的测试结果基本一致.同时由于其重量轻,体积小,特别适合于隐身产品的工程应用、生产检测、质量控制、维修和维护.     

水中石油类污染物的光纤荧光在线测量技术研究

根据水中石油类污染物质的光谱特性,采用荧光光谱技术,结合光纤传感技术和CCD探测技术,研制了一种可用于现场测量水中石油类污染物质的荧光光谱测量仪器。鉴于现场环境的特殊性,设计了水中自动取样预处理系统,可以实现真正意义上的实时分析,方便了现场操作。通过现场实验和性能测试,证实了其可行性,可以对水中石油类污染物质进行现场测量,从而进行污染物质的定性识别与定量分析,为水中污染物质监测提供了新的技术手段。     

Composite Optical Bend Loss Sensor for Pressure and Shear Measurement

A composite optical bend loss sensor for measuring 3-D forces has been developed. The sensor is composed of two optic fiber meshes which are embedded into a polydimethylsiloxane (PDMS) slab. The sensor consists of an array of optical fibers lying in perpendicular rows and columns sandwiched inside an elastomeric pad. A map of normal and shear stress is constructed based on observed macrobending through the intensity attenuation from physical deformation of two adjacent perpendicular fibers. Due to the new addition of the composite design and acrylic holder, the stability of the present sensor is found to be significantly better than our previously reported microfabricated optical bend loss sensor. In this paper, we will report the results of an optical bend loss simulation using the beam propagation method based on a series of images captured by a CCD camera on the fiber's bending curvatures. The result from the simulation will be compared with the results obtained from the experiment. Other results include vertical force and shear measurements at a single pressure point of the sensor. A force image algorithm is used to map the force distribution detected by the sensor. Here, we will present the results of six different shape patterns and two force magnitudes on each shape using a neural network system. We will also present a radio frequency sensor module, which we developed for the composite optical bend loss sensor for remote sensing.     

空间分辨率之比对遥感图像融合质量的影响

本文主要探讨光学遥感图像融合中空间分辨率之比对融合质量的影响.采用IKONOS-2全色与多光谱图像,通过重采样的方法模拟空间分辨率之比连续变化的融合输入数据,并进行Gram-Schmidt融合实验,补充已有成果中空间分辨率之比变化不连续、融合方法单一的现状.结果表明:当空间分辨率之比降低时,融合质量随着下降,实际应用中,多光谱图像的空间分辨率越高越好;当空间分辨率之比很小时,应适当降低全色图像的空间分辨率,以减弱融合图像的光谱变形,提高融合质量;此外,即使空间分辨率之比很小,融合后图像也比融合输入多光谱图像的清晰度高,更利于图像判断与后续处理.     

Limits of Spatial Resolution for Thermography and Other Non-destructive Imaging Methods Based on Diffusion Waves

In this work the measured variable, such as temperature, is a random variable showing fluctuations. The loss of information caused by diffusion waves in non-destructive testing can be described by stochastic processes. In non-destructive imaging, the information about the spatial pattern of a samples interior has to be transferred to the sample surface by certain waves, e.g., thermal waves. At the sample surface these waves can be detected and the interior structure is reconstructed from the measured signals. The amount of information about the interior of the sample, which can be gained from the detected waves on the sample surface, is essentially influenced by the propagation from its excitation to the surface. Diffusion causes entropy production and information loss for the propagating waves. Mandelis has developed a unifying framework for treating diverse diffusion-related periodic phenomena under the global mathematical label of diffusion-wave fields, such as thermal waves. Thermography uses the time-dependent diffusion of heat (either pulsed or modulated periodically) which goes along with entropy production and a loss of information. Several attempts have been made to compensate for this diffusive effect to get a higher resolution for the reconstructed images of the samples interior. In this work it is shown that fluctuations limit this compensation. Therefore, the spatial resolution for non-destructive imaging at a certain depth is also limited by theory.     

A Measurement Technique for Structural Return Loss in Transmission Lines

A new method is described that will measure and locate the source of structural return loss in transmission lines in the presence of mismatch between the measuring bridge impedance and the average characteristic impedance of the transmission line. A conceptual measurement system that realizes the described method is also presented.     

离子束溅射沉积干涉光学薄膜技术

离子束溅射技术是近些年发展起来的制备高质量光学薄膜的一种非常重要的方法,它具有其它制膜技术所无法比拟的优点。但是,国内外对这方面的的研究和介绍甚少,且鲜见报到,本文着重介绍了离子束溅射技术的发展、原理和特征以及应用前景。     

Measurement of the Energy Resolution of Silicon X-Ray Detectors Using Absorption Edge Spectra

Measurement Techniques - A silicon detector with a longitudinal silicon wafer has been developed. x-Ray spectra at the K-absorption edges of Au, Pb, and Bi are used to measure its energy...     

基于频闪成像技术的MAV气动外形三维视觉测试(英文)

在目前的实验条件下虽已掌握了大量的气动外形测试数据和分析结果,但这些实验都是基于高速影像设备来完成物体运动记录的.为此,提出了一种基于频闪成像探测技术的柔性气动外形三维视觉检测方法,基于此方法,能够在不具备高速影像设备的条件下获取微小型飞行器(MAV)柔性气动外形的连续图像数据,使用尺度不变特征转换(SIFT)方法提取出描述表面纹理特性的特征点,在频闪图像中的各个不同位置依次进行搜索、匹配,找出特征点的同名点.为了提高跟踪精度,使用了RANSAC方法对误匹配对进行消降.实验结果表明,该方法不仅能实现柔性外形的形态学变化检测,而且能建立一幅频闪图像中不同位置上提取出的特征点之间的关系,从而计算出气动外形上特征点的运动轨迹.整个实验框架是基于双目立体视觉测量原理来满足检测与跟踪的高精度及可视性的.     

长度计量技术浅析

长度计量在工业生产、日常生活中应用广泛,对技术的发展和进步作用巨大。文章介绍了长度计量技术的意义、任务、相关的原理和测量基础,阐述了常用的长度计量技术。     

基于高斯光脉冲延迟技术的光纤长度精确测量方法

提出了一种基于高斯光脉冲延迟技术的无盲区、高精度光纤长度测量方法。借助光纤延迟环的作用,在高速示波器上可以观察两路具有相对时延的高斯脉冲序列。通过调节脉冲频率可使两路高斯脉冲完全重合,依据此时脉冲频率可计算出光纤长度。脉冲未完全重合则会引入频率测量的误差,而利用脉冲时延与幅度的转换关系,通过脉冲幅度极大值的测量可以精确判断脉冲是否重合。脉冲频率的分辨力达到0.1 Hz,从而提高光纤长度测量的精确度。实验中当光源波长为1296nm时,该方法测量2284.34m G.652单模光纤长度的不确定度为0.04m,测量12726.57m的不确定度为0.24m。     

光纤器件回波损耗测量系统分析

介绍了各种光纤器件（光无源器件、有源器件、光纤集成器件等）回波损耗的测量原理和测量方法。提出了一些关键技术的解决方法和试验方案。对各种不确定因素进行了分析和试验验证，最终建立了一套光纤器件回波损耗测量装置。     

Optical Intensity-Based Measurement of Multipoint Hetero-Core Fiber Sensors by the Method of Time-Differentiation in Optical Loss

In this paper, we propose the multipoint optical intensity-based measurement of tandem connected intrinsic fiber-optic sensors by means of monitoring time-differentiation in optical loss. The use of hetero-core sensors can make it possible that a simple optical intensity-based measurement combined with a time-differentiation method could be facilitated for the multipoint measurement because the hetero-core technique has a low insertion loss and a sizable loss change in the tandem usage. Addressing multi-sensors has been successfully demonstrated including one displacement sensor and two contact sensors, which are located along a single transmission line in real-time basis. The gait system is also efficiently improved to monitor the knee flexure and the sole contact sensors located in a single transmission line with a mirror at the terminal end of fiber in order to simplify the measurement system for unconstrained monitoring.     

不可分离结构的损耗因子测量研究

提出对不可分离结构内损耗因子和耦合损耗因子的测量方法。对于内损耗因子测量，针对实际工程中子结构不可分离的问题，提出了用总损耗因子代替内损耗因子的方法。对于耦合损耗因子测量，利用已测得的内损耗因子结合稳态振动实验测得的能量可计算出结构间耦合损耗因子。同时分析了耦合损耗因子大小对总损耗因子代替内损耗因子差值的影响。仿真结果表明，当耦合损耗因子远小于内损耗因子时，内损耗因子和总损耗因子近似相等。对双圆柱壳耦合结构进行了实验验证，实验结果证明了该方法的正确性。     

光干涉法测量微机械零件变形的研究

介绍了用光干涉法测量微加速度计零件变形的研究。将准直单色光投射入由一玻璃片和被测件之间形成的空气楔中，被测件表面和玻璃片底面反射的光发生干涉，由面阵CCD接收。用快速傅立叶变换（FFT）图像处理方法得到被测微悬臂梁的三维形变图。该方法可对微小器件的微位移作分辨办为10nm的测量，并直观的显示测量结果。     

基于成像式照度测量的菲涅尔光学助降系统设计

为了解决菲涅尔光学助降系统的检测问题,提出了一种基于成像式照度探测法的菲涅尔灯发光强度测量方案,并研制了成像式照度探测装置。试验结果表明该装置可远距离对大口径、大发光角度的菲涅尔灯进行发光强度的探测,满足菲涅尔光学助降系统检测装置测量的要求。